Wash the mung beans thoroughly and soak them in water for 4 hours. Drain well.
In a pressure cooker, add the soaked mung beans along with 2 1/2 cup of water and a pinch of salt. Cook over medium-high heat until you hear the first whistle. Then reduce heat to low and wait for the second whistle.
Turn off the heat and allow the pressure to settle naturally. When you open the pressure cooker if there's excess water, cook uncovered until it evaporates. Test for doneness by pressing a green gram between your fingers; it should be soft.
Crush the jaggery and make a syrup by boiling it with 1/2 cup of water over low heat. Strain the syrup to remove any impurities.
Reheat the jaggery syrup and add grated coconut and cardamom powder. Cook for 2 minutes, stirring constantly.
Add the cooked mung beans to the syrup mixture. Mix well until a thick consistency is achieved. You can also check by rolling a small amount into a ball; it should hold its shape well. Remove from heat and let it cool.
Shape the mixture into 15-20 balls using your hands. Grease your hands with ghee or oil if the mixture is too sticky.
In a separate bowl, prepare the batter by mixing all-purpose flour with 3/4 cup of water, turmeric powder (optional), and a pinch of salt. Ensure the batter is thick like the consistency of Idli batter.
Heat cooking oil in a deep-bottomed pan. Once hot, reduce the flame to medium.
Dip each mung bean ball into the batter, ensuring it's completely coated, and deep fry until golden brown and crispy on all sides.
Remove the fried Sukhiyan using a slotted spoon and place them on paper towels to drain excess oil.
Serve hot as a delightful snack or dessert. Enjoy the crispy exterior and sweet, aromatic filling of Kerala Style Sukhiyan!